Characters might find themselves without food or water and with no means to obtain them. In normal climates, Medium characters need at least a gallon of fluids and about a pound of decent food per day to avoid starvation. (Small characters need half as much.) In very hot climates, characters need two or three times as much water to avoid dehydration.

A character can go without water for 1 day plus a number of hours equal to his Constitution score. After this time, the character must make a Constitution check each hour (DC 10, +1 for each previous check) or take 1d6 points of nonlethal damage.

A character can go without food for 3 days, in growing discomfort. After this time, the character must make a Constitution check each day (DC 10, +1 for each previous check) or take 1d6 points of nonlethal damage.

Theoretically, Grimvaalk's rations could feed both him and Fanax. But Fanax will be screwed if the party gets scattered for any length of time, or if something (for example) kills Grimvaalk and Fanax has to run away without his cousin's corpse.

That result yields a total of 15 HD worth of spirits, no one of which may have more than 9 HD. If Gorx calls anything with more than 3 HD, all his spirits will treat his orders as merely friendly suggestions; creatures with 3 HD or less will obey him without question unless he tells them to do something that's obviously suicidal.

Gorx doesn't have a shared language with these spirits, so he can communicate only basic commands, such as “Come here,” “Go there,” “Fight,” and “Stand still.”

Gorx will seal the pact with 7 of the 2 HD Earth Elementals. He'll point at the boar, then extend one hand, palm up. He then smashes his balled fist into his extended palm. He doesn't share a language, so he'll just say "Underestimate the boar."

Let's have a Charisma check to represent Gorx's facility at playing charades. Yonah, Cha'nek, Zathrus, Zathrus's horse, and the boar are all in the same general direction, after all. There's some room for confusion.

I think it would be more accurate to say that Grimvaalk and Zathrus can't take down a boar, in less than three full rounds.

It's not clear to me that Gorx's elementals are going to be fast enough to catch up to the critter, but if the battlefield were laid out in such a way that they could have arrived closer to the boar, the fight would already be over. For that matter, it probably would already be over if the bugbears had been able to get into melee with the boar.

As it is, this is not a difficult kill (none of you has even taken damage), so much as it is taking a long time for you to pile on enough damage to make the piggy fall over.